Histopathology Flashcards
What are the specific lengths of the rods and where they are pointing towards?
8 micrometers towards the surface
4 micrometers towards the DEJ
As we grow old, the enamel becomes more permeable. T or F
false
These defects start from the outer portion of the enamel and up to the DEJ
Enamel lamellae
Describe Enamel Tufts
Defects found along the DEJ
Interrod substance is made up of?
Calcium hydroxyapatite and 0.5% organic substances
What is the function of the interrod substance?
Keeps the rods together
Dentin has the same mineralization as?
Bone
Dentinal fluid flows ________ the enamel surface
Towards
What are the surfaces in enamel?
Surface zone
body of the lesion
dark zone
translucent zone
Why is the surface zone a relatively unaffected area?
Due to the constant remineralization
It has a greater resistance due to greater degree of mineralization and greater degree of fluoride concentration.
The surface zone contains ______ calcium phosphate
Bulky, poorly defined
What does reprecipitation mean?
There is a small degree of remineralization but it is not enough unless there is an intervention
Body of the lesion is the area of greatest demineralization. How many percent?
20-50%
This is also known as the positive zone
dark zone
The dark zone is _________ % of demineralization
5%
Translucent zone is always present. T or F
False
How many percent of demineralization is Translucent zone?
1%
What are the layers in dentinal caries?
Bacterial biofilm zone
Zone 3
Zone 2
Zone 1
What is within the bacterial biofilm zone?
Conglomeration of bacteria
Other names of Zone 3 ?
Soft dentin
Infected dentin
Outer carious dentin
What occurs in Zone 3?
Low mineral content
Irreversible denatured content
Becomes necrotic and contaminated
What are the other names of Zone 2?
Firm dentin
Affected dentin
Inner carious dentin
What occurs in Zone 2?
Demineralization of Intertubular dentin
Initial formation of Intratubular fine crystals
Other names of Zone 1?
Hard dentin
Sclerotic dentin
Tertiary dentin
Reparative dentin
What are the differences between primary, secondary and tertiary dentin?
Primary - dentin produced during the development of the tooth
Secondary - Dentin produced after the tooth has fully developed
Tertiary - Dentin produced due to a noxious stimuli
What are found within the dentinal tubules in sclerotic dentin?
Hydroxyapatite crystals and Whitlocklite crystals
What initiates the sclerotic dentin?
When the pulp gets irritated
What is sclerosis?
Increase in inorganic material in that area
Until what layer can we excavate the dentinal caries?
Soft dentin or Outer carious dentin or Infected dentin or Zone 3
What are the advance changes in dentin? (3)
Decalcification of walls
Liquefaction foci
Ovoid areas filled with necrotic debris
This is the breakdown of dentinal tubules
Liquefaction foci
What is formed during liquefaction foci?
Liquefactive foci.
What are dead tracts?
Dead tracts are formed when the progression of caries is too fast that the dentin will not be able to launch it’s protective mechanism through hydroxyapatite and whitlocklite crystals
Reparative dentin is formed during __________ stimuli and are formed by _________ odontoblasts
Stronger stimuli and New
Reactionary dentin is formed by ________ odontoblasts in response to ________ stimuli
Surviving and mild
Is tertiary dentin and sclerotic dentin the same?
No. Sclerotic dentin is when the dentinal tubules get filled with hydroxyapatite and whitlocklite crystals while Tertiary dentin is when hydroxyapatite and whitlocklte crystals are deposited at the base.
This is our body’s defense mechanism
Inflammation
